Evaluating Low-Carbon Transportation Technologies When Demand Responds to Price

Production and possible reduction of greenhouse gases produced during GI endoscopy activity: a systematic review of available literature

BACKGROUND AND AIMS

Greenhouse gases (GHGs) that trap heat in the atmosphere are composed of carbon dioxide (CO2), methane, nitrous oxide and fluorinated gases (synthetic hydrofluorocarbons, perfluorocarbons and nitrogen trifluoride). In the USA, the health sector accounts for 8.5% of total GHG emissions. The primary objective of this systematic review was to critically analyse the carbon emissions data from GI endoscopic activity.

DESIGN

The GI endoscopy carbon cycle was evaluated at preprocedural, intraprocedural and postprocedural levels. We performed a systematic literature search of articles published on these issues until 30 June 2022 and discussed these available data on endoscopy unit GHG carbon cycle, barriers to reduce GHG emissions and potential solutions. The inclusion criteria were any full-text articles (observational, clinical trials, brief communications, case series and editorials) reporting waste generation from GI endoscopy. Abstracts, news articles and conference proceedings were excluded.

RESULTS

Our search yielded 393 records in PubMed, 1708 in Embase and 24 in Google Scholar. After application of inclusion and exclusion factors, we focused on 9 fulllength articles in detail, only 3 of them were cross-sectional studies (all from the USA), the others reviews or position statements. Therefore, the quality of the studies could not be assessed due to heterogeneity in definitions and amount of emissions.

CONCLUSIONS

Recognition of carbon emissions generated by GI endoscopy activity is critical. Although multiple limitations exists for quantification of these emission, there is an urgent need for collecting proper data as well as examining novel methods for reduction of these emissions for a sustainable endoscopic practices in the future.

Tunnel measurements reveal significant reduction in traffic-related light-absorbing aerosol emissions in China

Light-absorbing aerosols (LAA), including black carbon (BC) and brown carbon (BrC), profoundly impact regional and global climate. Vehicle emission is an important source of LAA in urban areas, but real-world emission features of LAA from the urban vehicle fleet are not fully understood. This study evaluates traffic-related BC and BrC emission factors (EFs) and their vehicular emission inventories via road tunnel measurements in Tianjin, China, in 2017 and 2021. The distance-based and fuel-based EFs of BC for the mixed fleet were 1.05 ± 1.28 mg km^-1 veh^-1 and 0.057 ± 0.057 g (kg-fuel)^-1, respectively, in 2021, with a dramatic decrease of 80.6 % compared to those in 2017. The BC EFs for gasoline vehicles (GVs, including traditional gasoline and hybrid vehicles) and diesel vehicles (DVs) were 0.55 ± 0.065 mg km^-1 veh^-1 and 10.5 ± 2.52 mg km^-1 veh^-1, respectively, in 2021. Compared to 2017, the BrC EFs also decreased significantly in 2021, by 10.8-53.6 %, with 0.32 ± 0.45 mg km^-1 veh^-1 and 0.018 ± 0.020 g (kg-fuel)^-1 of distance-based and fuel-based EFs for mixed fleet. The BrC EFs for GVs and DVs were 0.091 ± 0.024 mg km^-1 veh^-1 and 3.06 ± 0.91 mg km^-1 veh^-1, respectively, in 2021. Based on the BC and BrC EFs for GVs and DVs and annual mileage for each vehicle category, the annual vehicular LAA emission inventories were estimated. From 2017 to 2021, the annual vehicular LAA emissions in Tianjin have been significantly reduced, by 69 % for BC and 10 % for BrC. DVs account for a small amount of the vehicle population (8.4 %), but contribute to most of the BC (83 %) and BrC (86 %). Our study demonstrates the significant reduction of vehicular light-absorbing aerosols emission due to vehicle pollution prevention and control in China.